The Lost Hero is an American fantasy-adventure novel written by Rick Riordan, based on Greek and Roman mythology. It was published on October 12, 2010, and is the first book in The Heroes of Olympus series, a sequel to the Percy Jackson & the Olympians series. It is preceded by The Last Olympian of Percy Jackson & the Olympians and followed by The Son of Neptune. The novel has since been translated into many languages and released as a hardcover, e-book, audiobook and paperback.

The story follows Jason Grace, a Roman demigod with no memory of his past. He, along with Piper McLean, a daughter of Aphrodite, and Leo Valdez, a son of Hephaestus, are given a quest to rescue Hera, the queen of gods, from the clutches of Gaea, the primordial goddess of the earth. It is the first book in the Camp Half-Blood chronicles to use third-person narration, switching between the points of view of Jason, Piper, and Leo.

The Lost Hero received positive reviews from critics for its complex and mature plot when compared to its predecessors. Criticism was focused on its stretched action sequences and dialogues. At its peak, the novel has appeared first on The New York Times bestseller list, the USA Today bestseller list, The Wall Street Journal bestseller list, and the Publishers Weekly bestseller list. It was named the best children's book of 2010 by Barnes & Noble and won the Junior Young Reader's Choice Award in 2013.

Plot[edit]

Jason Grace awakens on a school bus which belongs to the Wilderness School, unable to remember anything about his past. He is next to Piper McLean, his apparent girlfriend, and Leo Valdez, his apparent best friend. All three are part of a class field trip to the Grand Canyon. After they arrive there, a classmate, Dylan, turns into a storm spirit and attacks the trio and their trip leader, Coach Gleeson Hedge. In the ensuing fight, Jason battles the spirit and surprises everyone with his powers. Hedge is revealed to be a satyr and is captured by the storm spirit as it flees. A flying chariot with two demigods appear on the scene. The female demigod, Annabeth Chase, expresses her frustration upon seeing that her missing boyfriend, Percy Jackson, is not there as she had hoped, as he has been missing for three days without a trace. Jason, Piper, and Leo are told that they are Greek demigods and are taken back to Camp Half-Blood. There, Leo is revealed as a son of Hephaestus, Piper as a daughter of Aphrodite and Jason as a son of Jupiter, though Hera, the Greek form of Juno, tells him he is her champion.

Leo, who has the rare ability to conjure fire, does not use nor tell anyone about it out of guilt about his mother's death seven years prior. Meanwhile, Jason finds out about his sister Thalia Grace, a daughter of Zeus and lieutenant of the Hunters of Artemis. In the woods, Leo discovers a damaged mechanical bronze dragon and rejuvenates it. Shortly thereafter, the three are given a quest to rescue Hera from danger. After encountering Boreas, Piper, Jason, and Leo discover that their enemies are working under orders from Gaea, the Greek primordial goddess of the Earth, to overthrow the gods. Throughout their journey, they overcome numerous obstacles and eventually manage to save Coach Hedge, and also meet Thalia and the Hunters, who have also been looking for Percy. Thalia and Jason reunite for the first time since Jason was two, but they are separated on the way to Aeolus's castle. After almost being imprisoned by Aeolus under Gaea's orders, the trio manage to escape and end up in San Francisco.

They defeat the giant Enceladus at Mount Diablo and rescue Piper's father, who was being held captive. After saving Piper's dad, she gave him a potion given to her by Aphrodite and he forgot about the mythical world. Jason, Piper and Leo, with the Hunters of Artemis, travel to the Wolf House and defeats the forces of Gaea, saving Hera. They temporarily stall Gaea's plans, but are unable to completely destroy the ancient beings. Meanwhile, at camp, Leo creates plans for a ship that can sail to Greece, and the Hephaestus campers decide to build it, appointing Leo as their new counselor. With part of his memory returned, Jason realizes that he is a son of Jupiter, a hero from a Roman counterpart camp to Camp Half-Blood called Camp Jupiter somewhere near San Francisco. Hera, known as Juno to the Romans, has switched him with the Greek hero Percy Jackson, who is now at the Roman camp with no memory of his previous life. Camp Half-Blood and Camp Jupiter have had a ruthless rivalry, and whenever they came into contact, things never ended well.